Automatically controlled plant thinning and cultivating machine



Dec. 26, 1950 F BONCOMPAlN 2,535,720

AUTOMATICALIJY CONTROLLED PLANT THINNING AND CULTIVATING MACHINE Filed Aug. 27, 1946 5 Sheets-Sheet 1 Dec. 26, 1950 F. BONCOMPAIN 2,535,720

AUTOMATICALLY CONTROLLED PLANT THINNINGJ AND CULTIVATING MACHINE Filed Aug. 27, 1946 5 Sheets-Sheet 2 Dec. 26, 1950 F. BQNCOMPAIN 2,535,720

. AUTOMATICALLY CONTROLLED PLANT THINNING AND CULTIVATING MACHINE Filed Aug. 27, 1946 5 Sheet s- Sheet 3 2 a 30 f 2.9 I 2a Fimllq'o 5 Ban/can Pom I v van/174K Dec. 26, 1950 F BONCOMPAIN 2,535,720

AUTOMATICALLY CONTROLLED PLANT THINNING AND CULTIVATING MACHINE Filed Aug. 27, 1946 5 Sheets-Sheet 4 Film 5:015 Bum m/v flan 1w:

fi EM 4 SW Dec. 26, 1950 F. BONCOMPAIN 2,535,720

AUTOMATICALLY CONTROLLED PLANT THINNING AND CULTIVATING MACHINE Filed Aug. 27, 19 16 5 Sheets-Sheet 5 auge/s Ba vc c n PnM/ 28 11m M BM Patented Dec. 26, 1950 AUTQMATICALLY CONTKQLLED PLANT THENNING AND CULTIVATING MA- EHINE Francois Eoncompain, Saint-Quen, France; as-

signor to Andr Marie Auguste Ferte, Terny par Margival, France Application August 27, 1946, Serial No; $93 ,364 In France July 26, 1945 Section LPubIic Law 90; August 1946 Patent expires J 113! 26, 1965 11 Claims.

B invention has for its object a thinning and cultivating machine of the type including re tractable tools adapted to be automatically set in their operative position for digging the ground and upro'oting the plants therein or else for raising or retracting said tools in order to preserve certain plants. Suchmachines are of particular i'hterest, for the cultivation of beetroots and the like plantssown in rows.

My invention has for its object a machine of this type" wherein the member controlling the plants to be uprooted or else to be protected, is

co'nstitutedby a feeler which when entering into contact with the plant closes a circuit provldcd with a suitable amplifier controlling a relay capahie of producing the retracting or raising movement of the operating tools; said machines include moreover means for automatically rend eting said circuit inoperative after it has operated once for protecting a plant so that the following plantsmay be removed over a predetermiried interval. Such a machine allows exeouting automatically theselection or thinning out of the young plants which is of particular interesnt i the cultivation of plants sown in rows seen for instance as heetroots which grow ext'remely thick and of which anumber should be removed for allowing the remaining plants suffi'cient" room for their growth. The meansconsidered may be electro-mechanical and include arelay which is actuated during the passage of a feeler overthe first plant and starts the drive of a cam which provides after a certain travel the openin of the circuit controlling the retraction of the tool.

The following description and accompanying drawings" given out b'y way ofexample and by no means inia limitati-ve manner will allow the manher of executing the invention to be well understood.

Insaid drawings:

Fig. 1 is an: elevational View of a feeler adapted to close. the control circuit when it enters into contact with a plant.

Fig. 2 is a part sectional plan view thereof.

Fig. 3- is a wiring diagram of the machine.

Figs. 4 and 5 are views projected on two perpendicular planes of the driving means providing for the delayed breaking of the control circuit.

Fig. 6 illustrates the manner of adjusting said driving means.

Fig. '7= is a view in horizontal diagrammatic cross-section: of a row of plants adapted to 11- .lustrate the operation of the machine;

Fig. 7a is a diagrammatic side elevation view of a machine according to the" invention. M

Fig. 8- is a diagrammatic cross-sectional view it auenow arrangement ensuring the retraction of the" operating tools.

Fig. 9 shows a modification of the wirihg diagram eli'shring the delayed breaking of the co'n trol circuit.

Referring to Figs. 1", 2 and: 7a, the machine comprises a frame 61 adapted to be hooked to tractivemearis and which is Supported by avewheels tile. The rear portion of this frame 61% su-rifpoits the rotary drum 5| provided with tools; 58. The drum 5| is" driven in rotary fash- 1 03-1 by any suitable means, for erem le by the wheels 6a of thema hine, withith'e aid of chain are, shaft 6|'e,fq131'ld. chain an; Beneath the machine, forwardly of the drum 51" is the electrical feeler i, carried by the frame 61" anticonstantly moistened by water contained in the tank 5.

The roller H likewise carried by the chassis,

said rolier' serving to close the control circuit of the amplifier through the plant contacted by thefeeler' I", and the soil. The machine includes acontact member or feeler constituted by a perfdratid metal tube 1', closed at bdth ends and covered at its periphery with a coat 3 formed of a capillary materiarsuch are an agglomerati'on of fibers similar tothatforming lamp wicks. Theieelerthu'sconstituted by: the system of the t'uhe and wickshaped' coat therefor, is secured hdriz'zori-tally to the name 61 or the machine, which moves on the greener in the direction of the arrow marked irrFigs; l, 2 and 7a.. Thetube I is preferabiy connected through its medial part re second tube a leasing s a eservoir 55 under load securecl tethe' frame (fl. This reservoir 5 is filled water or another electrolyte whereby the wick 3 forming the outer sii'rface of the feeler is cbnstantly Kept moist; This wick is adapted to come into contact-with the plants and to this end the" tube and the wick are secured to the machine at a suitable level above ground so that the middle of the time I may" coincide substantially in horizontal projc'tien (Fig. 2) with the row of plants X--X which to be operated u pcn by the machine;

To the front of the feler the direction Of operation of the machine and ate s'uitable'height is arranged a screen 6 of insulating material which serves to lay the plants down before the wick 3- comes into contact therewith so that-the contact between thebent plar'it and the machine may be obtained as far" as possihle" on the vertical passing through the foot of the plant; thus 3 the contact may be produced at a distance from the operating tools 50 which is accurately defined and which is equal in the case considered to the interval separating the feeler from the tool system, the feeler moving with the machine in the direction of the arrow along and above the row of plants XX. In Fig. l, a plant is moreover shown as folded or laid down by the screen 5 and the contact may be obtained in this case between the plant and the feeler above the foot of the plant. The electric control circuit may be arranged in a casing 62 on the frame of the machine. As illustrated in Fig. 3, it includes an amplifier consisting of a thyratron I the biasing of the control grid of which is controlled by the feeler I of the type described hereinabove, through the agency of the resistance R2. The grid circuit of the thyratron is closed through the potentiometer 8 which serves also for giving a negative biasing to the grid as disclosed here- .inbelow. The anodic circuit includes the electromagnet 9 controlling the switch II). This switch controls a second relay II which when energized produces the retraction of a number of the tools 50 and the same switch I also controls a further relay I2 when the hand-controlled switch 2a is closed, as explained below. The action of the relay I2 is to break the anode circuit after a certain delay as will be disclosed hereinafter. The cathode is heated by the alternating current taken off one of the secondaries Ilia of a transformer I3 the primary of which receives the alternating current collected from the rings [4a of a motor-generator I4 provided :with commutators. motor-generator receives through the commutator his the driving current from a storage hat- The driving part of said tery I5 provided on the agricultural machine.

'This storage battery is also used for energizing the relays II and I2 when the switch III is closed. 4

Through a second collector Me the motor-genera- I tor I l feeds direct current under a suitable voltage into the anode circuit of the thyratron I.

The second secondary I31) of the transformer l3 produces through the agency of the dry rectifier I6 and of the potentiometer 8 an adjustable voltage which serves for biasing the grid of the thyratron with reference to the cathode.

Supposing first the hand operated switch .23, is

'open whereby the relay I2 is de-energized, the

switch 3436 is closed and the switch I210 leading to the anode is also closed, the operation of the machine is as follows:

When the feeler I is not in contact with any plant, it is apparent from inspection of the draw- .ing that the grid is brought by the potentiometer 8 and through the resistance RI and R2 to .a negative potential with reference to the oathode. This potential is adjusted through displacement of the slider of the potentiometer 3 to a value underneath the critical value which corresponds to the voltage applied between anode and cathode whereby no discharge may pass through the thyratron. The tools of the machine are thus allowed to work in the ground. When the feeler I touches a plant to be respected, such as a beet root if the machine is used for operating on beet root lines, the slider of the point 83.. This current is amplified by the time-- tron I, because the potential of the grid of the thyratron becoming less negative, the discharge passes instantaneously, in the anode circuit of said thyratron. The relay 9 is thus energized, its contact I0 closes and the relay II energized in its turn controls the retraction or the raising of the tool so as to preserve the plant touched by the feeler. Relay control devices as shown at II, are known which allow retracting the operative tools when said relay is energized. The operative tools may be constituted for instance by the arms 50 (Fig. 8) arranged after the manner of spokes at the periphery of a drum 5I the axis of which is parallel to the axis of the machine and which is rotatingly driven by the machine itself around the stationary shaft Ela, secured to the frame of the machine, when the latter moves over the ground. These arms are pivotally secured at 52 to the drum and are submitted to the action of springs 53 which urge them into a folded position for which they lie parallel to the axis of the drum and in this retracted position they do not work in the ground as illustrated for the tool 50 at the lower part of the drum of Fig. 8. A latching system 54 associated with each tool ensures in opposition to the spring 53 the radial location of the corresponding tool. A movable abutment 55 controlled by the armature of the relay II is located in the path of the projections 56 rigid with the latch 54 when the relay is energized and produces thus through actuation of said projections the pivoting of the latch 54 and the release of the corresponding tools. The latter are retracted by the springs 53 when during the rotation of the drum the rollers 58 carried by the tool support and rolling over a stationary cam 59 (secured to the stationary shaft 5Ia) arrive on to the lower part of this cam and are allowed to rock while the upper part of said cam returns the tools into their projecting operative position inside which they are locked by the latch 54 if the electromagnet II is deenergized. The number of retracted tools depends obviously on the are described by the drum 5I while the stop 55 is held back by the relay II i. e. during the duration of energization of said relay or during the time of contact of the feeler I with the plant or plants to be preserved.

Arrangements of this type are known per se, and it is not necessary to describe them to any further length.

It is important that as soon as the contact between the feeler I and the plant has ceased that the discharge in the thyratron may be extinguished. It is known that once a thyratron is energized by a suitable biasing of the grid it remains in said energized state until the anode current passes through zero. Therefore, if the source of energy inserted in the anode circuit of a thyratron is a source of direct current as in the case illustrated in Fig. 3, the discharge once initiated is no longer stopped whatever may be the biasing impressed on the grid. In the circuit illustrated in Fig. 3, the voltage taken off the commutator Me of the motor-generator I4 is transformed into a pulsatory voltage through the following arrangement; there is arranged in parallel with the winding of the relay 9 a condenser 9a, the circuit of which can be closed by a switch I21). The self induction of the electro-magnet 9 and the capacity of the condenser 9a are selected so as to form together an oscillating circuit of high frequency say 1,000 periods 'onceit has been initiated by the feeler l.

3 per second for instance. The voltage impressed on the anode of: the thyratron. with reference to the cathode passes thus from a maximum. to zero at the frequency of. said. oscillating circuit. Consequently as soon as the biasing of the grid which has initiated the discharge is removed, the thyratron ceases discharging as soon as the anode voltage passes through its following zero e. after a. time which may be as reduced as, de-

sired and depends only on the frequency of the oscillating circuit Q-9a..

. Obviously, it is necessary for the distance between the'feeler and the plane in which the tools operate tobe adjusted in conformity with the angle of rotation of the drum 5|. corresponding to the time elapsed. between the moment at which thetool receives its retracting movement from therelay i I. and. that at whichitpasses in its co- ..operating position. with reference to the ground one of the plants to be respected and it is on the 1 contrary rendered operative between said plants whereby the ground may be worked. inside such intervals.

But there is another problem which arises when the plants sown inrows grow in thick formation and this problem consists in removing some of these plants. while allowing the growth of the remaining plants. This is the usual operation of thinning executed, in beetroot growing and known in France under the name of demariage."

A row of beetroots, to be thus thinned out,.

appears generally as shown in Fig. 7. There exists at 18 a first plant followed up to I51 by a number of plants growing very near one another. From I!) to 20 there are no plantsat all, by reason of a. faulty germination. At 28 there is a further plant beginning a further row of thickly growing plants up to 21 and so on. It is necessary that when the machine arrives in register above the plant It said plant maybe preserved ,While the following plants should be removed through a distance e, the plant following said distance. at 22 is preserved the following plants are removed over a further distance c and the plant 23 at the end of said distance is preserved;

, the following plants are again removed, the plant standing at 20 at the beginning of the second plant row Zii--2l is preserved, the plants being removed again through a distance 9 and so on.

The problem thus laid open issolved by the faction of the relay i2 whichin accordance with the precedingly described manner of operating has been supposed to be inoperative by reasonof the opening of the hand-controlled switch [22,. 1 When this switch [22, is closed, the relay [2 is energized together with the relay I l assoon as i the feeler meets the first plant of the row,

say plant It. Moreover, in this manner of operation, the switch 12b inseries with the condenser 9a is opened whereby the action of the osci1lating circuit 9--9a is cut oil? and the discharge through the thyratron is no longer extinguished As soon as it is energized, the relay l2 displaces its armature 21a (Fig. 5) in the direction of the arrow fi -in opposition: to the actioneof the spring Ill) b1ade22. This armature moves; consequently out of the notch 23 provided in a rotary plate 24 which allows said: plate to:- be driven into: rotation by the cooperating. plate 251 constantly driven. by the machine in. the direction fa. (.The device shown in. Figs. 4. and 5 may be arranged in the casing 62 secured on the machine and the plate 25. actuated by a. suitable transmission with chain 339,, for example, as indicated in Fig. 7a.) A friction. disclze of agglomerated. cork felt or the like material is inserted for thispurpose between: the plates- 24 and 2.5- and a spring 21 urges the plate 2'4 against the disc 25. and the plate 25 through the agency of a ball. 28 (Fig. i). An extension 29 arranged axially of the. plate 2.4 shows a flat side surface 30.. A- stationary sector 3! adapted to be angularly setin the desired position round the common. axis on the plates carries a tongue 32' pivotally secured round a pivot 33. and provided at its free end with a movable contact piece 3 A spring 35- urgesconstantl-y said movable contact 3'4 against the stationary contact piece 36 rigid with. the sector 31. The movable contact 34 and the stationary contact 36 are inserted. inside the anode circuit of the thyratron T. The tongue 32 carries moreover a projection 3]" bearing against the axial. projection 29" of the plate 24' under the action of the spring 35,. said projection. 31 being such that at the start, when the plate 24 1s locked by the armature 2| of the relay [2 engaging the notch 23, the contacts of the switch (M -36 may be urged against one another so as toclose the anode circuit of the thyratron'. The flat surface Hallows such a closing of the contacts and when the plate 24 rotates, said closing is maintained during the rotation through the angle a corresponding to the: passage of the flatsurface 36 in front of 31. On the contrary beyond the rotary angle a and when the projection 3'! begins bearing on the cylindrical. part. of the extension 2'8, the tongue 32 is raised in: opposition to the action of the spring 35 and the. contacts 34-35 move away from one another.

The 'operation. of the arrangement is as follows:

When the first plant of a row such as theplant I8 is met by the. feeler, the relay l2 energized as disclosed hereinabove at the same time as the relay H, releases the plate 24' which is frictionally driven .and. begins rotating; At the same time, the relay H produces the; retraction of a number of tools proportional to the time. taken by. the plate 2'4"to. describe the. angle a as during this time the discharge continues insidethe thyratron. At the end of this time, the projections? on the tongue is raised by the cylindrical partof the projection 29 and the contacts 34-461 are moved apart. Consequently the; discharge of the thyratron is extinguished. andthe relay 9 is de-energized and some also the relays H and I2. While: the projection 31. is urged outward-1y by the cylindrical portiorr of the extension 29, the anode circuit remains open and the: machine operates blindy i. e. all thetools dig the ground. through the distance e. At the .end. of this distance, the plate 24 has described a complete revolution and is stoppedby the abutment of the notch 23 against the armature 2! of the relay l2.

It is possible to modify the number of tools retracted at the beginning of. adistance eeither by angularly setting the sector 3| so th=atthe projection 37 may assume at the start a position shown in. Fig. 6 for which the operative. angle of the armature carrying the contact 34.

is reduced to or else by replacing the plate 24 by another plate the flat surface of which shows an angle a of a different value. The distance 6 between the plants or beetroots to be preserved i. e. the path to be executed during the blind operation of the machine may be adjusted by inserting, between the plate 25 and its driving means controlled by the machine, a suitable speed change gear.

The machine described allows thus:

Either digging between suitably spaced plants, the switch l2a, being open while the switch I21: is closed and the sector 3! is positioned so as to ensure the closing of the contact pieces 3438;

Or else the thinning out of the thickly sown plants after closing of the switch '22, and opening of the switch i211.

Fig. 9 shows a modification of the delaying means for said latter manner operating the machine. This modification is of a purely electric constitution and its parts may be incorporated to the switch board of the machine or tractor. An iron-cored relay 4!] is adapted to attract its armature 4! which carries a movable contact 34 normally closing the circuit over the stationary contact piece 36 when inoperative and held in that position by a return spring 342.. A resistance 44 is inserted in series with the coil of said relay 40 and a condenser 45 is mounted in parallel with said coil.

If the thyratron is energized through the action of the electrolytic feeler acting on the biasing of the grid, as described hereinabove, the current from the source '40 flows inside the two parallel circuits constituted on one hand by the relay 4G with its condenser 45 and its resistance 44 and on the other hand by the electromagnetic control means 9 for the tools.

- Examining now the first of these circuits 4D44, 45, it is apparent that the current from the source I46 flows through the resistance 44 and the coil 40, which loads the condenser 45. This current decreases thus from a predetermined value up to the end of the charging of the condenser between the beginning and the end of the charging of the condenser the voltage at the terminals of the coil 40 will therefore increase from zero to a value which is that of the source I40 reduced by the amounts corresponding to the constant drop inside the thyratron and to the drop in the resistance 44. This value, at the end of the charging of the condenser, is sufiicient for allowing the attraction The opening of the switch 34-36 does away with the feed from the source but the armature returns into its inoperative position only after the condenser 45 has been sufiiciently discharged into the inside of the coil 40. The switch 34-36 plays the same part as in the case of Fig. 3. The first stage elapsing between the beginning of the energization of the thyratron and the opening of the switch is used for the retraction of the tools because during this time the relay 9 is energized through the discharge; the second stage separating the failing of the contact 34 from the next closing of the switch under the action of the return spring, corresponds to the digging of the ground over a certain distance and to the removal of the plants filling up said distance. For the adjustment of the apparatus shown in Fig. 9 four parameters are available, namely the ohmic resistance of 4d, the capacity of the condenser 45 which is adjustable through the incorporation of the auxiliary condensers 45a."

45s, the length of the gap of the magnetic armature 4| of the relay and the stress exerted on said armature by the return spring.

It is therefore possible to obtain through suitable values of these parameters a correct timing of the operation as required for the work in view.

The circuits are completed by switches allowing as desired the operation of the machine for digging between separate plants or else forthinning out the plants. In the first case, the switch [21, is closed as in the case of Fig. 3 and the switch 4% is opened so as to energize the relay 4!). In the second case on the contrary, the switch [2b is opened and the switch 46a is closed.

The storage battery described with reference to the preceding forms of execution may be omitted and all the electric members may be fed by a generator driven by the machine or its driving engine.

Obviously the above described forms of execution have been given out solely by way of examples and they may be modified in particular through the use of equivalent technical means without widening thereby the scope of my invention as defined in accompanying claims.

What I claim is:

1. An automatically controlled plant thinning and cultivating machine for digging selectively parts of a row of plants comprising a feeler of electrical conducting material adapted to engage the plants of a row, a source of electricity, an electric circuit connected to said source and to said feeler and adapted to be closed by the grounding of the feeler through a plant, an amplifier connected to said circuit, a relay the energization of which is controlled by said amplifier, digging tools adapted to be moved into inoperative position by said relay when energized and timing means for automatically deenergizing during a predetermined time said relay after the circuit has been closed over a plant to be protected against the action of the tools.

2. A machine as claimed in claim 1 in which the feeler is constituted by a metallic support and an outer lining of porous material thereon moistened with electrolyte.

3. A machine as claimed in claim 1 in which the timing means includes a second relay controlled by the amplifier, an armature therefor, a rotary cam adapted to be released by the attraction of the armature by the second relay, means driving the cam and means whereby the cam after a predetermined angular travel renders inoperative the amplifier circuit for allowing the return of the tools into their operative position.

4. A machine as claimed in claim 1 in which the timing means includes a second relay controlled by the amplifier, an armature therefor, a rotary cam adapted to be released by the attraction of the armature by the second relay, a plate constantly rotating under the action of the machine engine and adapted to frictionally drive the cam and means whereby the cam after a predetermined angular travel provides for the breaking of the amplifier circuit.

5. A machine as claimed in claim 1 in which the timing means includes a second relay controlled by the amplifier an armature therefor, a rotary cam adapted to be released by the attraction of the armature by the second relay, a plate constantly rotating under the action of the machine engine and adapted to frictionally drive the cam and a switch in the amplifier circuit adapted to be opened by the cam after a predetermined angular rotation of said cam.

6. A machine as claimed in claim 1 in which the timing means includes a second relay controlled by the amplifier, an armature therefor, a rotary cam adapted to be released by the attraction of the armature by the second relay, a plate constantly rotating under the action of the machine engine and adapted to frictionally drive the cam, a switch in the amplifier circuit adapted to be opened by the cam after a predetermined rotation of said cam and means for angularly shifting the last mentioned switch with reference to the cam.

'7. An automatically controlled plant thinning and cultivating machine for digging seectively parts of a row of plants comprising a feeler of electrical conducting material adapted to engage the plants of a row, a source of electricity, an electric circuit connected to said source and to said feeler and adapted to be closed by the grounding of the feeler through a plant, an amplifier connected to said circuit and including a thyratron, the grid of which is connected with the feeler, a direct current source feeding the during a predetermined time said relay after the circuit has been closed over a plant to be protected against the action of the tools and including a high frequency oscillating circuit in series with the thyratron anode adapted to transform the direct current feed into a pulsatory voltage for interrupting the discharge in the thyratron when the pulsatory voltage passes through zero immediately after the grid biasing produced by the grounding of the feeler circuit is cut out.

8. A machine as claimed in claim 7 in which the timing means includes a second relay controlled by the amplifier, an armature therefor, a rotary cam adapted to be released by the attraction of the armature by the second relay, means driving the cam and means whereby the cam 10 after a predetermined angular travel renders inoperative the amplifier circuit for allowing the return of the tools into their operative position and switches controlling respectively the operativeness of the second relay and of the oscillating circuit.

9. A machine as claimed in claim 1 in which the timing means comprises a second relay controlled by the amplifier for breaking the amplifier circuit and adjustable means for delaying to the desired extent the energization and de-energization of said second relay.

10. A machine as claimed in claim 1, in which the timing means comprises a second relay controlled by the amplifier for breaking the amplifier circuit, adjustable means for delaying to the desired extent the energization and de-energization of said second relay, a capacity inserted in parallel with the first relay for forming a circuit the oscillations of which are adapted to allow the return to starting conditions of the amplifier when the feeler is no longer grounded and switches controlling the operation respectively of the second relay and of the oscillating circuit.

11. A machine as claimed in claim 1, in which the timing means comprises a second relay fed by the amplifier for breaking the amplifier circuit and a condenser connected in parallel with said second relay, whereby the energization and deenergization of said second relay are delayed as a function of the capacity of the said condenser.

FRANCOIS BONCOMPAIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 565,671 Cummings Aug. 11, 1896 886,179 Bragunier et al Apr. 28, 1908 1,519,198 Franke Dec. 16, 1924 2,007,383 Opp July 9, 1935 2,177,803 Ferte et a1 Oct. 31, 1939 

